Yarn twisting apparatus are known which operate by the single twisting method, and wherein the package carrier and the feed yarn packages are rotated about the twisting axis. Apparatus are also known which operate by the double or "two for one" twisting method, in which the package carrier is floatingly supported on the rotating twisting spindle, and held against rotation by external forces.
Yarn twisting apparatus operating by the double twisting method are particularly suitable for the described use, since the feed yarn package carrier does not rotate, thus permitting the spindle to reach relatively high speeds, even when the mass of the feed yarn packages is not balanced on the package carrier. As a result, two differently filled yarn feed packages may be employed, and similarly, only a few of the several package supports on the carrier may be employed.
A special advantage of the double twisting devices resides in the fact that the apparatus may be arranged with its axis extending obliquely or horizontally, and it is preferred that a weight be used for holding the package carrier against free rotation, with the weight being positioned to be offset from the rotational axis of the spindle.
To impart a defined twist to a yarn with the above described twisting apparatus, it is necessary that its yarn delivery speed and the rotational speed of the twisting spindle be at a defined ratio, which determines the degree of twist imparted to the yarn. The speed of the advancing yarn and the rotational speed of the spindle therefore need to have a constant value, or at least a predetermined value, with respect to each other. For example, the yarn advancing speed and the spindle speed may be interconnected by mechanical means, or by an electrical linkage. Also, the yarn twisting apparatus may be used to produce yarns with special color effects from a plurality of differently colored yarns, and which may be further processed by hand, for example, by a hand knitting operation, or the yarn may be wound to balls, preferably also by hand.
In the embodiments which are adapted for use by home workers, it will be understood that the output requirements greatly fluctuate in time, as a result for example of the working speed of the knitter, or by the technical conditions of the knitting apparatus. Also, present twisting apparatus of the described types are unable to readily permit varying color effects in the knit product, and in the past, color effects could be achieved only by employing balls of differently dyed yarns, and wherein the yarn of each ball was of the same color over its entire length.
It is accordingly an object of the present invention to provide a yarn twisting apparatus of the described type, which renders it possible to easily change the coloring of the yarn by exchanging the yarn feed packages, and to make the thus produced twisted yarn directly available for further processing.
It is also an object of the present invention to provide a yarn twisting apparatus of the described type, wherein the produced yarn is supplied in accordance with the user requirements, which may fluctuate in time.